Method of treating separators for storage batteries.



F. WRIGHT.

ME THOD 0F TREATING SEPARATORS FOR STORAGE BATTERIES.

APPLICATION FILED IAN-9,1914- RENEWED MARLH, 1916'.

Patented 0ct.10,1916.,

WITNESSES A TTOR/VEVS onirnn STATES PATENT ornron. v

FREDERICK WRIGHT, OF POUGHKEEPSIE, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MENTS, T0 WRIGHT STORAGE BATTERY COMPANY, OF POUGHKEEPSIE, NEW YORK,

A CORPORATION OF NEW YORK.

1,2oo,cs2.

Specification of Letters Patent.

Patented Oct. 10,1916.

Application filed January 9, 1914, Serial No. 811,152. Renewed March 14, 1916. Serial No. 84,287.

' make and use the same.

The present invention relates to storage batteries and has for its object the production of a wood separator adapted for use between the plates of a storage battery to hold them out of contact when in action. Hard rubber and wood have both been used for this purpose but there has been difficulty in the practical use of wood because of the slow and progressive delivery by it to the acid of the battery of saps and organic acids and analogous components injurious to the battery and in some instances forming slimy coatings over theplates, and thereby greatly lessening their chemical activity and also interposing a barrier tothe flow of current. I

Onemethod of treating the wood heretofore proposed consists in soaking it in lye fora time to dissolve out some of the organic materials, and then washing fora long time in running water, but this has two 'serious disadvantages. In the first place,

the lye will not completely clear out the objectionable organic material, and in the second place the running water will notremove the lye from the pores of the wood, and it stays in the wood to come out later on in the battery with serious disadvantages thereto.

In accordance with the present invention, the. wood strips or spacers, prior to their assembly in a battery, are given a treatment which removes the sap,acetic acid, and other analogous materials, and leaves the wood in inert condition, veryporous and Well suited for prolonged use between lead plates immersed in dilute sulfuric acid. 7

For a better understanding of the present invention, reference may be had to the followingdetailed description, which is to be taken in conjunction with the accompanying drawings, where Figure 1 is a fragmentary elevation much enlarged showing one of the wooden separators and indicating the preferred physical outline thereof. This illustration is on a scale about three times larger than the separator itself. Fig. 2 is an enlarged section through the wood spacer, and Fig. 3 is a perspective view somewhat diagrammaticv of a cell wherein a operation may be carried out.

The woods best suited for the present purpose are cherry or bass Wood, preferably cherry, and this is cut into pieces 1 of an area to correspond with the battery plates to I be separated, and may have the dimensions of 4%"x5i These flat pieces are scored along one face to form a plurality of ribs 2, as shown in Fig. 2. When thus scored they may have a thickness of 3/64 of an inch between ribs, and a thickness of 5/64 of an inch measured through the ribs. .After being cut to the shape disclosed, the thin strips are still strongly charged with nativeacids, and if placed in contact with a storage battery plate of the lead type, will Warp and buckle through the action of these organic acids. The first step in their chemical preparation for use in the battery consists in soaking them for a long time in dilute sulfuric acid. I have found it advantageous to soak them for two Weeks in sulfuric acidv of a specific gravity 1.200. This length of time. allows the acid to penetrate into all.

parts of the strips and possibly opens up the pores somewhat, and removes some of the soluble material, but even after this prolonged soaking, the. strips are highly charged with objectionable matter which would come out if the strips were used as spacers in a battery without further prelimipart of the treating i current passed between the lead electrodes 3 and 4. With wooden strips of thedimensions above indicated it is advantageous to subject them to this electrolyzing action for from 42 to 5 days and nights at a current strength of 7 amperes. The current can be reversed from time to time with advantage.

When this electrolyzing action is begun, the

strips are already thoroughly permeated with theacid as the result of the prolonged. preliminary soaking, so that there is little impediment to the flow of current from one electrode to the other directly through the strips. This flow of current by electrolytic osmosis carries the saps and acids and other analogous organic materials out of the pores of the wood, and with this progressive opening up of the pores, the acid has better access to other parts of the fibrous structure and is able to clean out all of the deleterious matter leaving behind only a dead, porous woody structure, a sort of skeleton of the original wood strip. The organic materials thus removed go into solution in part, and collect as a scum on the top of the bath and the walls of the vessel, and can be skimmed off from time to time.

The wood spacers resulting from the process above set forth have been used with advantage in storage batteries of the lead type intended for high rates of discharge, and for this purpose they present a decided advantage over rubber, for they are of substantially uniform porosity throughout their entire area, and so allow all parts of the adjacent plates to bear equally the burden of the heavy current discharge. With perforated hard rubber there must of necessity be some localization of the current flow at the openings in the rubber preventing an absolutely uniform activity throughout the entire area of the plate, articularly when sists in soaking them for a long time in dilute sulfuric acid; and then subjecting them in-dilute sulfuric acid to the purifying action of electrical osmosis prior to their assembly in the battery.

2. The method of treating wood strips to render them suitable for use as separators in a lead storage battery, which consists in saturatingthem with dilute sulfuric acid, then assembling said strips side by side between a pair of electrodes immersed in dilute sulfuric acid, and passing current between said electrodes through said plurality of strips in series until the objectionable impurities have been electrolyzed out and the strips rendered suitable for assembly in a lead storage battery.

3. The method of treating wood strips to render them suitable for use as separators in lead storage batteries, which consists in soaking said strips for days in dilute sulfuric acid and then assembling said strips thus filled with acid into a pack between a pair of electrodes immersed in dilute sulfuric acid, and there passing current between said electrodes and through said pack of strips until by electrical osmosis the strips have been rendered porous and inert and suited for use in batteries; substantially as described.

In testimon whereof I aifix my signature, in presence 0 two witnesses.

FREDERICK IGHT.

Witnesses:

ALFRED BOLOGNESI, S. BL'mE. 

